This application claims the priority benefit of Taiwan application serial no. 89103702, filed Mar. 2, 2000.
1. Field of Invention
The present invention relates to a semiconductor structure. More particularly, the present invention relates to a plasma arcing sensor.
2. Description of Related Art
Since the deposition process by plasma has it characteristic of low temperature operation and the plasma etching is anisotropic etching, the processes with regard to plasma are widely used in fabricating semiconductor integrated circuits. The plasma process is carried out by forming ions or atoms with charges in the plasma chamber and followed by ion bombardment to the wafer. When the ions or atoms in the plasma chamber carry a great amount of charges, and the suspector, used to support the wafer, is biased, arcing happens between the wafer and such carriers. As a result, arcing causes damage of wafer during the fabrication of the semiconductor and leads to failure of product percentage to {fraction (1/1000)} high such that the productivity is seriously reduced. Thus, adjusting the conditions and parameters of the process to prevent from arcing is important.
However, it is quite difficult to monitor or study arcing phenomenon since it may not occur often, and normally it may happen once a while and then disappear. Repeatable experiment is nearly impossible since arcing is hard to predict due to its low possibility. Accordingly, when the process engineer changes conditions of the plasma process to reduce the arcing, it cannot be tested by repeated experiment.
The invention provides a plasma arcing sensor, thereby increasing the possibility of arcing in the plasma chamber.
The invention also provides a plasma arcing sensor to increase the possibility of arcing in the plasma chamber and helps engineers adjust the parameters of the process, thereby preventing from arcing in the plasma chamber.
As embodied and broadly described herein, the invention provides a plasma arcing sensor. A conductive layer is formed over a substrate. A top conductive layer, formed over the conductive layer, is isolated from the conductive layer with dielectrics. An insulating layer is formed to cover the top conductive layer. The area of the top conductive layer is smaller than that of the conductive layer.
The invention further provides a plasma arcing sensor. A plurality of conductive layers is formed over a substrate and such conductive layers are insulated by dielectrics. A top conductive layer, formed over the conductive layers, is covered by an insulating layer and isolated from the conductive layers with dielectrics. The area of the top conductive layer is smaller than that of the conductive layers.
This invention also provides a method of monitoring plasma arcing, thereby detecting the possibility of plasma arcing when an insulating layer is etched by plasma. A wafer having a plurality of plasma arcing sensors is provided, and each of the plasma arcing sensors has a top conductive layer with different charge density thereon. A plasma etching process is performed to the wafer to expose the top conductive layer and then neutralization between the top conductive layer and the plasma decides the possibility of plasma arcing.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.